This disclosure relates to polycarbonate articles, and in particular to polycarbonate articles that can be repeatedly sterilized and methods of manufacture thereof.
Polycarbonates are useful in the manufacture of articles and components for a wide range of applications, from automotive parts to medical devices. Because of their broad use, it is desirable to provide polycarbonates with improved thermal and hydrolytic stability. Medical devices in particular are desirably resistant to steam sterilization. Although some polycarbonate articles can be steam sterilized one time, the repeated steam sterilization of many polycarbonate articles generally results in a degradation of the advantageous physical and/or mechanical properties of polycarbonate.
Resistance to steam sterilization, for the most part, has been attempted by using materials that have higher glass transition temperatures and heat distortion temperatures. Some of these materials have been polyetherimides, polysulfones, Bayer APEC (a high heat polycarbonate) and polyphthalyl carbonate (PPC, a high heat copolyester polycarbonate). Generally though, these materials have drawbacks that prevent their widespread use in articles that are usually steam sterilized. For example, polyetherimides are colored, relatively expensive, and have low impact strength. Polysulfones color upon exposure to light, tend to be brittle, are viscous, and can absorb water. Bayer APEC is a stiff material that presents processing challenges and that can also be sensitive to hydrolysis, and certain copolyester polycarbonates tend to be brittle, colored materials. There accordingly remains a demand in the art for polycarbonate articles that do not exhibit significantly degraded physical and/or mechanical properties despite being repeatedly steam sterilized.